Carbureter.



W. T. MIXSELL.

GABBURETER.

APPLICATION FILED APR. 1o. 1911.

Patented Apr. 7

Gwen/252:

'carries at its lower end athrottle valve 8 WARD TEMPLE MIXSELL OF WASHINGTON, DISTRICT 0F. COLUMBIA,

-Speciication of yLetters Patent.

Patented Apr. 7, 193.4.

Application led April v10, 1,911.l Serial No. 620,186.

T o all whom 'it may concern Be it known that l, WARD TEMPLE MixsnLL, a citizen of the United States-residing at lVashington, District of. Columbia, have invented vcertain new and usefull Improvements in Carbureters, of which the following is a specification.

This invention relates to improvements in. such apparatus as are intended to associate definite amounts of hydrocarbons with free air to render a mixture of the same combustible within the cylinder of -an internal combustion engine.

- In the accompanying drawings- Figure 1 is a vertical section of the carbureter. Fig. 2 is a. section on the line 2-2 of Fig.'1. Fig. 3 is a section on the line 3-3 vof Fig. 1.

.In the drawings, 1 indicates atop casingv which incloses a medium pressure air chamber 33.

Q is a middle plate, 3 is the oil chamber and 4 its bottom plate.

5 isan invertedcup shaped differential. lvalve which is pressed aboveby a spring 6 which may be compressedy by a valve rod 7 which' extends downwardly through .the valve and through a guide 30. Said rod which controls the air inlet to` a high pressure air chamber 31, under. the middle plate 2.. The valve rod 7 works through a guide 30 andhas stop nuts 7 thereon, to limit its motion. vAn operating lever 10 is connected tothe valve rod, by means ofl pins 9, and said lever may be operated by any suitable means. The cup valve 5 inclosesa nozzle 32 projecting from the middle .plate 2,. the capacity of the nozzle being substantially equal to that of the space between the nozzlel and the cup valve, as more fully explained hereinafter. A baffle plate' 34 is interposed between the valve 5 and the outlet from the carbureter.

38 is an annular wall or chamber depending from the top of the casing 1 and leading to the outlet 39 which will be connected tothe intake pipe to the cylinder. Air passes from the chamber v33 to the chamber 39 through an annular space 35 at the bottom, between the lower edge of the chamber 38 and the outer surface of a rim 35', of smaller diameter, projecting upwardly from the plate 2 'and around the spray nozzle. where- .the fixed end of said camspringon the undersidethereof, the stem being clamped to the spring 16 by nuts 17. The cam'spring 13 is fastened at one end to the wall of the oil reservoir by a bolt 18 and at the ther end is connected to a rod 14', which has a nut 19 thereon under the end of the spring. The spring may be fixed at adjustment by a set screw 15 which screws through the wall of the reservoir andis integral with the rod.

The'oil pressure under the spray headis approximately equal to the total differential pressure less that due to the difference in level of the oil reservoir and the spray head, and if the diderential pressure is varied the pressurev against the spray head will be correspondingly varied, and if a simple spring were used to control the movement ef the spray head the degree of flexure of the spring would vary las the pressure against the head, which would permit too great an opening of the oil valve, so it is necessary to interpose a progressively increasing resistance to limit the spring flexure, to obtain the desired openingand oil discharge. I accomplish this by causing the spring 16 to act against Lthe ,cam 13. This spring cam 13 has a very slight rise which Amay be increased or decreased by the adjusting rod 1 4, l

but at any adjustment the spring cam will form a curve, and as the spring 16 bends upwardly against the same in consequence of the lift of the stem 12 the point of contact will advance along the cam and` thus progressively shorten the effective length of the spring 16 and thus increase its resistance accordingly. If apermanently formed earn were used its Idegree of curvature would only be correct for one adjustment, but by using a rather heavy spring for a cam it may be adjusted by the rod, to take a new form and vary its curvature for each adjustment.

14 is the oil tube extending from the oil reservoir to the spray head. It will be noted that the diameter of said outlt is somewhat less than'the diameter! of thel spray head,

so that the inclined surface of the latter overhangs or extends beyond the rim at the mouth of the oil tube.

3G is an annular air port which surrounds the spray head and communicates from the high pressure air chamber 31 tothe low pressure chamber 38;

The oil chamber is air tight, except for a hole 37 in the top, .which admits pressure from the chamber 31, whereby the pressure in the oil chamber is always equal to that in 'f sure chamber 3l and air nozzle 36, and the other through the differential valve 5, medium pressure chamber33, and annular passage 35, the chamber 33, being in effect, a valved by-pass between the air inlet and the low pressure chamber or outlet.

As will be observed this carbureter has five specific structures each of which performs a special function. The function of the primary valve 8 at the inlet port is to effect a reduction of air pressure wit-hin the carburet-er. The oil reservoir in other carbureters is subject to atmosphericv pressure at all times, but in my carbureter, is closed to the atmosphere and has an air-passage or port 37 opening from the pressure chamber 31. This serves to avoid an excess iiow of oil when the pressure within said chamber is reduced. The function of the automatic valve 5 is to cause a difference of pressure between the oil reservoir and the mixing chamber 38, to effect a iow of oil to the atomizingv device, and also to generate by .such difference of air pressure a suficient velocity of air thro-ugh the nozzle 36 to effect atomization. The purpose of the spray head and adjacent parts is to effect atomization and the regulation of the amount of oil atomized according to requirements. To prevent the liquid particles being precipitated upon the walls of the vacuum chamber 38 or other surfaces, is the function of the secondary air current, drawn in through the annular passage 35, which, bein of considerable volume, and being admitted to the vacuum chamber at the bottom and flowing upwardly forms a wall of dry air between the central current (rising from the nozzle 3G and spray head) and the wall of the chamber 38, and carries the liquid particles through the intake pipe to the motor4 cylinder. In those carbureters in which the throttle valve, baffle plates, or other devices are located between the spray nozzle and the cylinder, this result isv defeated, which is one of the reasons I put the throttle at the intake, and have the passa-ge beyond the nozzle unobstructed.

The function of the automatic valve 5 in my carbureter is that of a di'erential pressure valve, to cause that difference of pressure in the upper and lower chambers required to effect atomization, as the oil will flow to the spray-head in greater amount as the differential pressure is increased, and as the major volume of air to support combustion must pass this valve, it is necessary that this valve should be of such a form as will passa definite volume of air foreach definite increase or decrease in pressure, in order that a volumetric relationship between the air passed to ltheengine and the oil atomized may obtain; and in order t0 employ the variable carburetive method of motor control, itis requisite thatmeans be provided for automatically controlling the operation of the valve 5 according to the variations inl engine suction, and that means be further provided for manually controlling the operation to vary the rate of Carburation at will, The ordinary form of valve (the disk) will,l not perform this function satisfactorily, as the difference of pressure actuating the same is at a maximum when the valve is closed `and become progressively decreased, as the valve opens. vWhen such a valve is controlled directly by a spring, then, when the pressure against the valve is at a maximum, the spring tension is at a minimum, and as the pressure against the valve decreases, the spring tension is at a minimum, andias the pressure against the valve decreases, the spring tension increases, so that there is but one critical point in the travel of the valve where the two forces are in balance, and as this critical condition cannot continue, the valve is subject alternately to both forces and reciprocates or chatters, causing an unsteady delivery of air. It will also be appreciated that such a valve has no definite volumetric efficiency. To obviate this defect I have. devised the form of valve shown, which consists lof two nozzles or air passages, one (32) stationary, and the other, the valve proper (5) movable. lVhen closed the valve is subject to the full difference of static pressure between its inner and outer surfaces, but as itbegins to open, the pressure falls in both nozzles, the valve proper being subject to the static pressure existing above the .discharge orifice v of y the stationary nozzle, and, as the direction of the air current is changed 1800 it is also subject to a dynamic pressure, due to the momentum ot' the air particles at the velocity induced by the difference of static pressure, and when resisted by a spring, the tension of which varies directly as the degree of fiexure, it

will rise a definite height and discharge a determinable volume of air for each degree of difference of pressure. As the differential pressure operates to induce the fiow of oil to the atomizer, and as definite ratios ofcarburation must obtain, the volume of air passed by the valve must'be coordinated to the volume of oil which can be caused to flow in the atomizer. This oil volume will vary with a definite area of opening between the oil tube and the spray-head, as the square root of thel difference of pressure, increasing but twice in velocity and Volume when the pressure is increased in the ratio 1:4. It is obvious therefore that if the differential valve will pass eight volumes with a four fold increase of pressure while the oil volume increases only two fold, a decrease in the rate of Carburation would ensue; this condition is not desirable as a definite rate of carburation must obtain-for each degree of diderence of pressure. It is therefore necessary to provide a means for decreasing the differential valve opening, reducing the same so that the volume of air passed will' be in proper proportion to the volume of oil discharged; and therefore I' introduce a means of manually varying the rates of carburation to effect the power and speed variations of the motor by changing the relative position of the valve and its spring, manually, as regards the area of its opening, and thereby decrease the volume of air so as tofcause a definite ratio of Carburation to obtain for each degree pressure variation, this manual control being conveniently effected by connecting the differential and throttle valves, with a spring 6 to increase the resistance of the former as the latter is opened.

The operat-ion of the carbureter isv as follows: A reduced pressure being induced by the operation of the engine, air flows into the carbureter and oil fiows to the atomizer,

the differential valve 5 passing a definite volume of air, and the oil regulating device a' definite volume of oil, establishing a specific rate of Carburation. To increase the power of the motor the position of the differ-- ential valve vand its controlling spring is controlled, manually, by moving the same downward, by means of the lever 10, which opens the inlet or throttle valve 8 and at the same time tends to close the valve 5, which, reducing the relative volume of air passing said valve 5, increases the dierential pressure between the chamber 31 (and oil reservoir) and the chambers 33 and 38, causing an increased flow of oil, which, increasing the rate of carburation, causes an in crease of power.

1t is therefore evident lthat as the air volume and the oil volume are cordinated and for a given differential pressure are each identical in proportion, that it is possible to maiu- A decrease of power is effected by reverslng the former movement.I

tain a maximum ora minimum rate of carburation, at full speed, land a maximum or a minimum rate atlow speed, and any other degree of Carburation at any. speed. The relative degree of Carburation being manuallg controlled, the automatic action of the di 'erential Valve and the voil regulating mechanism maintain such rate, while varyling the relative Volumes of air and oil delivered to respond tothe varying speed changes of the motor.

. The 'action of the carbureter is such that it requires the lowest possible vacuum to operate; and the speed or power variation is effected in a manner to secure the highest thermal efliciency of operation, while the method of control will permit of a great degree of flexibility at low speeds. The opnozzle, and means tending to close said cup shaped member.

2. A carbureter, having high and low pressure chambers with a constricted passage therebetween, an oil nozzle discharging at said passage, a by-pass connecting the high and low pressure chambers around said passage, and a valve in said by-pass, comprising a nozzle, andan inverted cup shaped member surrounding and spaced from said nozzle, the effective area of the space between the nozzle and the cup shaped member being substantially equal to the effective area of the nozzle, and means to close the cup shaped member.

3.v 1n a carbureter, the combination of an oil nozzle, an air passage, having a contracted part surrounding said nozzle, a throttle controlling the inlet to said passage, a Vacuum chamber with an outlet pipe into which said nozzle discharges, said chamber and pipe being unobstructed beyond said nozzle, and a by-pass leading from the inlet end of-said passage and terminating in a secondary annular air outlet surrounding said contracted part of the air passage and spray nozzle and communicating with the vacuum chamber to form a c ntinuous annular enveloping air current in said chamber around the fluid drawn from the nozzle, to prevent precipitation of liquid particles on the surface of the vacuum chamber.

4. ln a carbureter, the combination of al one end and an outlet at the other end, an'

oil nozzle discharging into said passage, a by-pass extending around said nozzle, Whereby part of 'the flow of air will be through said by-pass, an automatic valve in said by-pass and controlling said How, a

spring pressing against the valve and tending to close the same, and means to manually increase the tensionof said spring, according to the extent of opening of the throttle. p

5.1n a carbureter, the combination of a passage having an air inlet at one end and an outlet at the other end, an oil nozzle'discharging into said passage, a by-pass extending around saidnozzle, whereby part of the flow of air willy be through said by-pass, an automatic valve in said by-pass and controlling said flow, a spring pressing against the valve and tending to close the same, and a manually operated throttle locatedat the air inlet, and connected through said spring with said automatic ,valve for control therewith.

6. In a carbureter, the combination of a mixing chamber, meansv to supply oil thereto, al primary air 'supply thereto, an additional lair passage leading-to the mixing chamber, and a valve controlling said pas-- sage, said'valve comprising a stationary nozzle, a movable cupped member or nozzle extending around said stationary nozzle and spaced therefrom, whereby the course of the air current is reversed as it asses through said nozzles, and means tending to close the movable nozzle. A

7. In a carbureter, the combination of a mixing chamber, means to supply oil thereto, an air throttling valve vcommunicating with the chamber, an auxiliary yielding air valve communicating with the chamber, and manually operated means including a connection between the throttling valve andthe auxiliary valve, to increase the tension of the auxiliary valve in proportion to the extent of opening of the throttling valve.

. 8. In a carbureter, .the combination of a 10W .pressure chamber, a spring controlled auxiliary air valve thereto, anl oil nozzle chamber, said air passage being provided with a Wall extending in the direction of the flow of air, a valve for said air passage and means tending to close'said valve, said valve lcomprising 'a surface against which the air impinges, and a flange. extending toward, substantially parallel with and spaced from-said wall, whereby the course of the air current is reversed as it passes saidvalve.

In testimony whereof, I aiiix my signa-v ture in presence of two Witnesses.

WARD TEMPLE MIXSELL.

Witnesses:

GEO. E. TEW, C. W. FowLER. 

